A genetic diagnosis that guides treatment and gives information on associated medical problems is now usual within days of being confirmed with diabetes.

Just 10 years ago it was typically more than four years before a genetic diagnosis was made.

For one couple from Belfast, a rapid diagnosis has made all the difference to their young son's treatment.

Paul and Michele Mulligan received a genetic result on then four-month-old baby Matthew within 10 days of taking him into hospital with a rash, and he was found to have high levels of blood sugar.

His consultant sent a sample to the world-leading diabetes genetic team at the University of Exeter Medical School.

Their swift genetic analysis discovered that Matthew's rare form of neonatal diabetes was caused by a mutation in a single gene, meaning he was not producing insulin and needed insulin therapy, but he will not have problems with his brain or gut unlike many children with genetic causes of neonatal diabetes.

The team recommended an insulin pump, which gives insulin through a cannula under the skin, sparing the family the trauma of injecting their son, now aged two, with insulin at meal times.

Mr Mulligan (30) said: "At first it was horrendous. As a parent, your biggest fear is that your baby is not healthy.

"With Matthew everything seemed fine. He was thriving - putting on weight and developing well, and the rash was the only sign that there was anything wrong. Taking him to hospital seemed like a precaution. Finding out he had a permanent form of diabetes felt like the worst thing in the world at the time.

"He was just so small and having constant insulin injections. His blood sugar levels were really unstable and he was like a pin cushion from all the blood tests.

"Although we were shocked and devastated that the genetic tests revealed the condition was permanent, it was a relief that the team recommended the insulin pump.

"By then we'd done our research and we felt that would be the best form of treatment.

"Having a swift diagnosis from the team at Exeter that was so precise was also extremely helpful. Knowing that it's just one gene that causes Matthew's condition is reassuring, as we know it's not got wider implications.

"We're also hopeful that one day this research may mean treatments can be more targeted."